1. Field of the Invention
This invention relates to hitching assemblies for agricultural implements of the pull-type (i.e. implements that are not self-propelled and usually not provided with an internal power source), by means of which such implements are attached to driven vehicles, e.g. tractors. More particularly, the invention relates to hitching assemblies that are capable of supplying hydraulic power to the mechanical elements of such implements.
2. Description of the Prior Art
The applicant herein has already disclosed a novel method of and apparatus for harvesting grain and seed crops that provide an alternative to the use of conventional combine harvesters. In this regard, reference is made to U.S. Pat. No. 5,794,423 issued on Aug. 18, 1998; U.S. Pat. No. 5,795,222 issued on Aug. 18, 1998; and U.S. Pat. No. 5,873,226 issued on Feb. 23, 1999 filed in the name of Robert H. McLeod.
A conventional combine harvester operates by carrying out all of the harvesting steps in the field on a continuous basis. The crop plants are cut, the cut plants are threshed to separate grain (or seeds such as peas, etc.), chaff and (inevitably) weed seeds from the stalks, the grain is then cleaned by separating it from the chaff and weed seeds, the grain is delivered to a waiting collection vehicle, and the stalks, chaff and weed seeds are returned to the field. The disadvantages of this are that (a) combine harvesters are very expensive to purchase and to operate; (b) they are not very efficient at cleaning the grain, so some grain is lost and/or further grain cleaning is required; and (c) chaff and weed seeds are returned to the field, so that their economic value is lost and weeds proliferate.
The concept underlying the systems disclosed in the above patents is that, instead of attempting to carry out all of the harvesting steps in the field, only the step of threshing and removing stalks is carried out, and the remaining product (a mixture of grain, chaff and weed seedsxe2x80x94referred to by the coined word xe2x80x9cgraffxe2x80x9d) is collected and transported to a fixed grain cleaning site. The advantage of this is that the harvesting equipment may be less complicated and expensive than a conventional combine harvester, the cleaning of the grain may be carried out more efficiently at a fixed site, the economic value of the chaff and weed seeds may be realized, and the need for herbicides is reduced (because the weed seeds are collected rather than being returned to the field).
The harvester employed in such a system may be of the pull-type, i.e. it may lack a motor or other propulsion means, and may simply be towed behind a powered vehicle, such as a conventional tractor, on undriven wheels. This can result in a considerable reduction of cost and improve maneuverability. However, a harvester of this kind still requires power to drive the cutting, threshing and conveying equipment, etc., and this may be supplied by a mechanical (rotary) drive line coupled to the conventional power take-off (PTO) of a farm vehicle and extending along a hitching arm used to pull the harvester behind the vehicle. When this is done, the mechanical drive line must be provided with joints (e.g. universal joints, constant velocity joints, etc.) that allow the rotating drive line to follow the contour of the hitching arm (for example, the arm may be of inverted generally U-shape to extend above the harvesting head of the harvesting unit), and that allow the hitching arm to pivot on the powered vehicle at one end and the harvesting unit at the other end. Such an arrangement is described in Applicant""s (as yet unpublished) U.S. patent application Ser. Nos. 09/590,362 and 09/590,186, filed on Jun. 9, 2000, and corresponding PCT application PCT/CA00/00679 filed on the same date.
While this is effective, the mechanical drive can generate a significant amount of vibration and noise, due to the many joints that are required and the large angles at which the joints may have to operate during turning of the vehicle or realignment of the harvesting unit relative to the vehicle. This also lead to rapid wear of the mechanical drive line. It would therefore be advantageous to provide an alternative way of transferring power to a harvester of this kind that minimizes or avoids such vibration, noise and wear.
Additionally, when using a hitching arm of the above kind, the mechanical drive line must usually undergo a sharp change of direction adjacent to the power take-off. The shaft of the power take-off is normally horizontal and faces outwardly from the rear of the vehicle. The hitching arm, however, extends generally upwardly from the hitch point, so the drive line must undergo a 90xc2x0 change of angle (or other sharp turn) to follow the contour of the hitching arm. At this very point (i.e. the hitch point), the equipment must accommodate large relative movements between the hitching arm and the vehicle as the harvesting unit can swing from side to side and tends to undergo rocking and bouncing during use. The use of conventional rotary direction-change devices (universal joints, gearboxes, etc.) to achieve the sharp change of angle may make it difficult for the mechanical drive line to accommodate all of the relative movements, since such devices often operate only through limited variations of angle.
Moreover, there are similar types of pull-type agricultural implements, e.g. machines that simply cut plants, such as disc mowers and windrowers, that would also benefit from the replacement or partial replacement of mechanical drive lines while still providing a means of transferring power from a driven unit to a towed (pull-type) implement.
An object of the present invention is to provide an alternative drive line for a pull-type crop harvesting unit, or other towed (pull-type) agricultural or other implement, that reduces or eliminates the vibration, noise and wear encountered when mechanical (rotary) drive lines are used for this purpose.
Another object of the invention is to provide a drive line that can readily accommodate all of the likely movements between the powered vehicle and an adjacent hitching arm used for pulling a crop harvester or other towed implement while following the contour of such a hitching arm.
According to one aspect of the invention, there is provided hydraulic drive apparatus comprising an elongated hitching arm for pivotal attachment at one end to a powered vehicle provided with a power take-off shaft and for attachment at an opposite end thereof to a pull-type agricultural implement having driven mechanical components, a hydraulic pump attached to said hitching arm adjacent to said one end, a rotatable drive shaft for actuation of said hydraulic pump upon attachment of said drive shaft to said power take-off shaft of said powered vehicle, hydraulic fluid lines for delivery and return of hydraulic fluid from and to said hydraulic pump for operation of said mechanical elements, and an articulated hitching assembly provided at said one end of said hitching arm for connection of said hitching arm to said powered vehicle, said assembly substantially isolating said rotatable drive shaft from movements of said hitching arm relative to said powered vehicle.
The mechanical drive shaft preferably has a first part for attachment to the power take-off shaft and a second part extending to the hydraulic pump, the first and second parts being coupled to each other at their adjacent ends with their longitudinal axes unaligned, the coupling being via a direction change device supported by the articulation assembly.
In the above apparatus, the direction change device is preferably a gearbox.
The direction change device (e.g. a gearbox) is preferably supportable by the articulation assembly at a preferred attitude relative to the power take-off shaft and relative to the hydraulic pump, and this preferred attitude is preferably maintained substantially unchanged during the movements of the hitching arm relative to the powered vehicle.
The articulation assembly preferably comprises an elongated plate for attachment to a draw bar of the powered vehicle at one end and having upstanding flanges at an opposite end, a cradle element pivotally supported between the upstanding flanges, the cradle having elongated cradle flanges extending from one end thereof, and a support unit (e.g. a housing) for the direction change device, the support unit being pivotally supported between the cradle flanges and also independently pivotally supportable from the hitching arm. The articulation assembly permits articulation about three mutually orthogonal axes, i.e. rolling, yawing and pitching. Most preferably, these three axes cross at a common point located at the center of the direction change device.
The articulation assembly may alternatively comprise a reel-shaped element for attachment to a draw bar of a powered vehicle, a saddle-shaped element surrounding said reel-shaped element and rotatable thereon, said saddle-shaped element having upstanding flanges provided with aligned bores, a pin extending through said bores of said saddle-shaped element, a hollow elongated housing having forwardly projecting lower side pieces pivotally connected to said saddle-shaped element via said pin, a cylindrical downwardly projecting element forming an end part of said hitching arm, and a bearing for rotatably attaching said housing to said cylindrical downwardly projecting element for rotation of said housing about said end element.
According to another aspect of the invention, there is provided a mobile agricultural implement of the pull-type having a body containing or supporting mechanical components, a hydraulic motor for operating said mechanical components, and an elongated hitching arm with opposite lateral ends extending from said body and pivotally connected at one end to the body and connectable at an opposite end to a rear portion of a powered vehicle, said hitching arm supporting a hydraulic drive apparatus for powering said hydraulic motor, said drive apparatus comprising a hydraulic pump attached to said hitching arm adjacent to an end of said arm remote from said agricultural implement, a rotatable drive shaft for operation of said hydraulic pump upon attachment of said drive shaft to said power take-off shaft of said powered vehicle, hydraulic fluid lines for delivery and return of hydraulic fluid between said hydraulic pump and said hydraulic motor, and an articulated hitching assembly for connection between said powered vehicle and said hitching arm for substantially isolating said rotatable drive shaft from movements of said hitching arm relative to said powered vehicle.
According to another aspect of the invention, there is provided an agricultural implement of the pull-type having a mobile body containing or supporting mechanical components for acting on a plant crop, a hydraulic motor for operating said mechanical components, and an elongated extending hitching arm with opposite lateral ends for pivotal connection at one end to the body and at an opposite end to a rear portion of a powered vehicle, said hitching arm carrying a hydraulic drive line for driving said hydraulic motor as a sole means of driving said mechanical components. According to another aspect of the invention, there is provided an articulation assembly for an equipment drive line, for connection between a powered vehicle and an elongated hitching arm used for pulling a harvesting unit by the powered vehicle, the articulation assembly comprising a direction change device for the drive line causing the drive line to change direction at the device, an elongated plate for attachment to a draw bar of the powered vehicle at one end and having upstanding flanges at an opposite end, a cradle element pivotally supported between the upstanding flanges, the cradle having elongated cradle flanges extending from one end thereof, and a support unit for the direction change device, the support unit being pivotally supported between the cradle flanges and also independently pivotally supportable from the hitching arm.
According to yet another aspect of the invention, there is provided, in a mobile harvesting apparatus comprising a harvesting unit of the pull-type containing or supporting mechanical components for cutting and processing a crop, a hydraulic motor for operating the mechanical components, an elongated extending hitching arm with opposite lateral ends for pivotal connection at one end to the harvester body and at an opposite end to a powered vehicle, and a drive line following the hitching arm for transferring power from the powered vehicle to the mechanical components of the harvesting unit, wherein the improvement comprises the use of a hydraulic drive line as the exclusive means of transferring the power from the vehichle to the mechanical components of the harvesting unit.
According to yet another aspect of the invention, there is provided an articulated hitching assembly for connection between a powered vehicle and an elongated hitching arm used for pulling an agricultural implement by said powered vehicle, said articulated hitching assembly comprising a first element for attachment to a draw bar of said powered vehicle, a second element pivotally attached to said first element for rotation about a first axis, and a third element pivotally attached to said second element for rotation about a second axis, and a pivotable connection for pivotal attachment of said third element to an adjacent end of said hitching arm permitting pivotal attachment of said third element to said hitching arm about a third axis.
By the term xe2x80x9cpower take-offxe2x80x9d (PTO) we mean a rotatable drive shaft provided on a tractor or other vehicle for the purpose of providing a source of mechanical power to ancillary equipment used in farming or the like. The PTO is usually provided with some kind of coupling for attachment to a driven shaft and is often partially or fully surrounded by a protective collar to prevent injury. The PTO is often connected to a main motor of the vehicle, often through a clutch or interrupter. The PTO shaft usually projects at right angles from the vehicle body facing to the rear.
The invention, at least in its preferred forms, makes it possible to provide power to the mechanical elements of a pull-type agricultural implement, such as a harvesting unit, without substantial noise, vibration and wear. The preferred articulation assembly isolates the mechanical drive for the hydrostatic pump from movements of the vehicle and hitching arm. The resulting assembly is self-contained (all the elements required for the hydraulic drive are attached to the hitching arm), merely requiring attachment to the ubiquitous power take-off of farm vehicles. The articulation assembly (which functions as a movement isolation device) allows a hydraulic (hydrostatic) pump to be mounted rigidly on the hitching arm without risk of damage from mis-alignments of the drive shaft used to power the pump caused by relative motion between the hitching arm and the vehicle.